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    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
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    <script>
      //1先创建两个变量
      var apple1 = '青苹果'
      var apple2 = '红苹果'
      //2创建一个临时变量
      var temp

      temp = apple1    
      apple1 = apple2
      apple2 = temp
      console.log(apple1)
      console.log(apple2)
    </script>
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